GCN Circulars
GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
21235 results found.
- Fermi GRB 240421B: Global MASTER-Net observations report
- Swift GRB 240421B: Global MASTER-Net observations report
- GRB 240421B: Fermi GBM Observation
- GRB 240421B: Swift-XRT refined Analysis
- GRB240421B: BOOTES-5/JGT optical upper limit
- GRB 240421B: J-band upper limits from WINTER
- GRB 240421B: Swift/UVOT Upper Limits
- Fermi GRB 240421A: Global MASTER-Net observations report
- EP240417a: no counterpart detection by SOAR
- EP240420a: Xinglong decaying optical counterpart
- GRB 240421B: Swift detection of a burst
- EP240420a: Nanshan optical counterpart observations
- GRB 240421A: Fermi GBM Final Real-time Localization
- EP240420a: NOT optical counterpart candidate and potential host
- Fermi trigger No 735280430: Global MASTER-Net observations report
- GRB240419A: Skynet Optical Afterglow Analysis
- GRB240418A - Candidate afterglow from NIRES
- IceCube Alert 240419.98: Global MASTER-Net observations report
- GRB 240419B: Swift/UVOT Upper Limits
- GRB 240419A: Swift/UVOT Upper Limits
- GRB 240419B: Swift-XRT refined Analysis
- GRB 240419B: optical afterglow from the NOT
- LIGO/Virgo/KAGRA S240420aw: Retraction of GW compact binary merger candidate
- Swift GRB 240419B: Global MASTER-Net observations report
- Swift GRB 240419A: Global MASTER-Net observations report
- GRB 240418A: Swift/UVOT Upper Limits
- GRB 240419A: REM NIR afterglow detection
- GRB 240419A: Swift-XRT refined Analysis
- GRB 240418A: Swift-XRT refined Analysis
- GRB 240419B: Swift detection of a burst
- GRB 240411B: Swift/UVOT Detection
- Fermi trigger No 735089036: Global MASTER-Net observations report
- EP240414a: GMG observation
- GRB 240419A: Swift detection of a burst
- GRB 240418A: NOT optical upper limits
- GRB 240418A: AKO Upper Limit
- GRB 240411A: GOTO early optical upper limits
- Swift GRB240418.85: Global MASTER-Net observations report
- GRB 240418A: Swift detection of a burst
- Fermi GRB 240417A: Global MASTER-Net observations report
- Improved IPN triangulation of GRB 240411A
- GRB 240417A: Fermi GBM Final Real-time Localization
- GRB 240415A: Glowbug gamma-ray detection
- GRB 240414A: Glowbug gamma-ray detection
- GRB 240415B: GECAM-B detection
- EP 240416a: Xinglong and NOT decaying optical counterpart
- GRB 240415A: Swift-BAT refined analysis
- EP240416A: MASTER optical observations
- GRB 240411A: Glowbug gamma-ray detection
- GRB 240414A: Swift-BAT refined analysis
- EP240416a: Kinder optical counterpart candidate
- GRB 240414A: AbAO optical upprer limit
- GRB 240415A: Swift/UVOT Detection
- GRB 240415A: Fermi GBM Observation
- GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
- GRB 240414A: GMG observation
- GRB 240415B: Swift ToO observations
- GRB 240415B: Swift/BAT-GUANO Correction
- GRB 240415B: Swift/BAT-GUANO arcminute localization of a short burst
- GRB 240415A: OHP/T193 optical observations
- GRB 240414A: Fermi GBM Observation
- Fermi GRB 240415A: Global MASTER-Net observations report
- GRB 240415A: Mondy optical transient detection
- GRB 240414A: Swift/UVOT Detection
- LXT 240402A/GRB 240402B: Swift follow-up observations
- GRB 240414A: Mondy optical observations
- GRB 240414B: Fermi GBM Final Real-time Localization
- GRB 240414A: AKO Optical Upper Limit
- GRB 240415A: Prompt Swift-XRT observations
- GRB 240415A: Swift detection of a burst
- GRB 240415A: Fermi GBM Final Real-time Localization
- EP240413a: Upper limits from GECAM-B Observation
- EP 240414a: NOT optical counterpart confirmation
- GRB 240414A: Swift-XRT refined Analysis
- GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
- EP240413A: GOTO optical upper limits
- GRB 240414A: Skynet Optical Afterglow Observations
- Fermi trigger No 734754044: Global MASTER-Net observations report
- Swift GRB 240414A: Global MASTER-Net observations report
- EP240414a: Kinder optical counterpart candidate possibly associated with the galaxy SDSS J124601.99-094309.3
- IPN triangulation of GRB 240410A
- IPN triangulation of GRB 240411A
- GRB 240414A : MITSuME Akeno optical upper limits
- GRB 240414A : OHP/T193 redshift determination
- GRB 240414A : OHP/T193 optical counterpart detection
- GRB 240414A: Swift detection of a burst
- LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240413p: Zwicky Transient Facility observations
- EP240408a: GSP optical upper limit
- IceCube Alert 240412.23: Global MASTER-Net observations report
- GRB 240411B: Swift-BAT refined analysis
- GRB 240411B: Swift-XRT refined Analysis
- GRB 240411B: 1.3m DFOT Optical observations
- GRB 240411B: OHP/T193 optical observations
- GRB 240411B: LCO optical afterglow detection
- GRB 240411B: Swift detection of a burst
- GRB 240408B: GRBAlpha detection
- GRB 240411A: Fermi GBM Final Real-time Localization
- EP240408A: MASTER optical observations
- EP240408a: Upper limits from GECAM-B Observation